The Central Asian Regional Security Complex Revisited:Understanding the Implications of the US Retreat From Afghanistan

On February 29,2020,President Donald Trump announced the United States signed a peace agreement with the Taliban,signifying the United States‟intention of leaving Afghanistan in the near future.Though the global pandemic has altered US withdrawal plans,the question still remains:What will become of the Central Asian regional security complex following America‟s exit?Buffered by the presence of the United States since 2001,the Central Asian republics now once again find themselves at a crossroads to either rely on individual defense services or to develop increased military cooperation with interested states.Recognizing Central Asia‟s history of collaboration among its regional and near-regional countries,I argue that the Central Asian Republics of Afghanistan,Kazakhstan,Kyrgyzstan,Tajikistan,Turkmenistan,and Uzbekistan will seek to develop stronger security ties with neighboring regional security complexes(RSCs),namely the South Asian,Russian,and Chinese RSCs.With decreased American influence,each of the states in these RSCs is rushing to fill the void of influence in order to capitalize on Central Asia‟s geostrategic position in Eurasia as well as secure itself from the threat of non-state actors still prevalent in the region.I further argue that the states in the Central Asian RSC additionally seek these same benefits and security,but receive them to a much lesser extent than their more powerful regional neighbors.Understanding how the American withdrawal from Afghanistan will impact Central Asian RSC relations can provide insight into how great power vacuums are filled both by great powers and regional powers alike.

Growing Regional Security Strength

At its August summit, the ShanghaiCooperation Organization shows it’s still astandard-bearer for regional

Regional Security Dilemma and Security Ownership——Some Observations on the Possibility of the U.S.Return to Asia-Pacific

The discussions of U.S.return to Asia-Pacific unfold more around the state to state relationship,and are lack of studies based on regions.This paper intends to analyze the connections between regional security dilemma and regional security ownership,and further examine how it is possible for the United States to return to Asia-Pacific.Although the United States during the early years of the end of the Cold War overlooked the importance of its Asia-Pacific strategy,however,the Asia-Pacific countries in short of consensus on regional security and a post-Cold War extensive security dilemma enable the United States to return to Asia-Pacific,improve and upgrade its U.S.-led regional security system.But,as far as China is concerned,the U.S.return to Asia-Pacific itself is both a challenge and an opportunity.

Regional ecological security anddiagnosisof obstaclefactors in underdevelopedregions：acasestudy in Yunnan Province,China

In order toclarify regional ecological security status and formation mechanism of regional ecological security barriers in underdeveloped regions of China,we took Yunnan province as a case to evaluate its regional ecological security by using entropy matter-element model,comprehensive index and GIS spatial method,and we diagnosed itsobstacle factors through obstacle degree model. We found a low overall level of regional ecological security in Yunnan. Only Kunmingfell into the good level, 68% of the regions were below the critical safe level. For the vast majority of regions in Yunnan, their regional ecological security was unstable. The indexes related to per capita resources, geological and topographyenvironment, economic, and technologywere at the unsafe or dangerous level.The indexes related to urban expansion, level of income, cultivated land quality were at the level of critical safety. The indexes concerning urban management capacity, airqualityand waterenvironment were at the good or ideallevel. Yunnan's regional ecological security was not good due to natural obstructive environment itself, simultaneously lower backward economic and social level restricted the ability of ecological security response to manage ragile ecological environment. The results of the composite index wereroughly consistent with those of the entropy weight matterelement model. The mean values of the classification index,from high to low, were: the state index>the response index>the pressure index. The state index and the response index had a significant mutual promotion to each other.The regions with good composite index, state index and response index mainly distributed in the central regions of Yunnan Province. Spatial autocorrelation of regional ecological security level in Yunnan was not obvious. Water resources, economic and social development were main obstacle factors of the regional ecological security.When distinguishing with obstacle type, Kunming belonged to natural ecological environment barrier type, while other regions belonged to economic and social barrier type.

Bilateral and Regional Strategic and Security Relationship Between China and the US after the Cold War

Sino-US relations are complex relations with multi-aspects between the two bigcountries in the world. It has three levels: the global level, the Asia-Pacificlevel and the bilateral level. The critical relationship between China and the US isembodied in the regional and bilateral levels that are more specific and essential.Beyond the field of economy and trade, their relationship is mainly embodied in thestrategic and security field.

Toward a Security Community in Asia? The Limits of Constructivism, Developmental Statism, Liberalism, and Realism

This article asks whether a regional security community has emerged in Asia with the potential to grow mature and seeks to make a contribution to the ongoing debate on this controversial topic.It advances the argument that states in this broad region are far from being able to develop a security community for reasons different from those provided by political realists,developmental statists,liberals,and constructivists(social,discursive,and emancipationist).The role of Association of Southeast Asia(ASEAN)and that of China provide excellent test cases for the theoretical proposition that the building of a successful regional security community requires at least two necessary conditions:liberal democracy and regional democratic leadership,which remain absent in Asia.

Theory and Method of Power System Integrated Security Region Irrelevant to Operation States:An Introduction

How to comprehensively consider the power flow constraints and various stability constraints in a series of power system optimization problems without affecting the calculation speed is always a problem.The computational burden of probabilistic security assessment is even more unimaginable.In order to solve such problems,a security region(SR)methodology is proposed,which is a brand-new methodology developed on the basis of the classical point-wise method.Tianjin University has been studying the SR methodology since the 1980s,and has achieved a series of original breakthroughs that are described in this paper.The integrated SR introduced in this paper is mainly defined in the power injection space,and includes SRs to ensure steady-state security,transient stability,static voltage stability,and smalldisturbance stability.These SRs are uniquely determined for a given network topology(as well as location and clearing process for transient faults)and given system component parameters,and are irrelevant to operation states.This paper presents 11 facts and related remarks to introduce the basic concepts,composition,dynamics nature,and topological and geometric characteristics of SRs.It also provides a practical mathematical description of SR boundaries and fast calculation methods to determine them in a concise and systematic way.Thus,this article provides support for the systematic understanding,future research,and applications of SRs.The most critical finding on the topological and geometric characteristics of SRs is that,within the scope of engineering concern,the practical boundaries of SRs in the power injection space can be approximated by one or a few hyperplanes.Based on this finding,the calculation time for power system probabilistic security assessment(i.e.,risk analysis)and power system optimization with security constraints can be decreased by orders of magnitude.

Quantitative analysis of the dynamic change and spatial differences of the ecological security: a case study of Loess Plateau in northern Shaanxi Province

Using the theory and method of the ecological footprint, and combining the changes of regional land use, resource environment, population, society and economy, this paper calculated the ecological footprint, ecological carrying capacity and ecological surplus/loss in 1986-2002 on the Loess Plateau in northern Shaanxi Province. What is more, this paper has put forward the concept of ecological pressure index, set up ecological pressure index models, and ecological security grading systems, and the prediction models of different ecological footprints, ecological carrying capacity, ecological surplus and ecological safety change, and also has assessed the ecological footprint demands of 10,000 yuan GDE The results of this study are as follows： （1） the ecological carrying capacity in northern Shaanxi shows a decreasing trend, the difference of reducing range is the fastest; （2） the ecological footprint appears an increasing trend; （3） ecological pressure index rose to 0.91 from 0.44 during 1986-2002 on the Loess Plateau of northern Shaanxi with an increase of 47%; and （4） the ecological security in the study area is in a critical state, and the ecological oressure index has been increasing rapidlv.

Security Rate Optimization of D2D Communication Based on Power Control

An optimization of device-to-device(D2D) security rate algorithm based on power control is provided to enhance the physical layer security underlaying D2D communication and guarantee the data rate requirement of the cellular user(CU) at the same time.First,a scenario model is set up,in which an eavesdropper is considered to wiretap the information of D2D transmitters.Then,a secure region of D2D communication is proposed.When D2D communication users reside outside the secure region,the spectrum of CU's is not allowed to share with the D2D communication so as to avoid eavesdropper tapping useful information of D2D communication.When D2D communication users reside inside the secure region,the security rate of D2D is maximized by optimization of the transmitting power of D2D and CU.The simulation results showthat the achieved D2D security rate of the proposed algorithm increases 2.8 bps/Hz when the signal to noise ratio(SNR) is 15 d B,compared with that when the random access algorithm is used.

Robustness Assessment of Wind Power Generation Considering Rigorous Security Constraints for Power System: A Hybrid RLO-IGDT Approach

Fossil fuel depletion and environmental pollution problems promote development of renewable energy(RE)glob-ally.With increasing penetration of RE,operation security and economy of power systems(PS)are greatly impacted by fluctuation and intermittence of renewable power.In this paper,information gap decision theory(IGDT)is adapted to handle uncertainty of wind power generation.Based on conventional IGDT method,linear regulation strategy(LRS)and robust linear optimization(RLO)method are integrated to reformulate the model for rigorously considering security constraints.Then a robustness assessment method based on hybrid RLO-IGDT approach is proposed for analyzing robustness and economic performance of PS.Moreover,a risk-averse linearization method is adapted to convert the proposed assessment model into a mixed integer linear programming(MILP)problem for convenient optimization without robustness loss.Finally,results of case studies validate superiority of proposed method in guaranteeing operation security rigorously and effectiveness in assessment of RSR for PS without overestimation.Index Terms-Hybrid RLO-IGDT approach,information gap decision theory(IGDT),operation security,robustness assessment,robustness security region(RSR).

Security Region: An Intelligent Approach to Transportation Networks

This paper proposes a security region of transporta-tion networks,which is defined as the set of flow states(operating points)satisfying the N-1 security in transportation networks.The boundary of the set is closed,inside all the operating points are N-1 secure;oppositely,outside all the operating points are insecure.First,N-1 security of the transportation networks is defined,which means that when a road is blocked,vehicles on other roads within the networks can also reach their destination through different paths without being trapped on the road.Then,the security region of transportation networks is modeled.The algorithm of a boundary calculation is studied and the boundary equations of security distances are proposed.Finally,the proposed security of the transportation networks is presented in different examples.This paper demonstrates the following:1)the security region can be accurately predicted by the simulation of N-1;2)the boundary distance can show the necessary degree of security;3)security can be improved by a preventive control scheme.The simulation on TransCAD is used to verify the correctness of the results.Index Terms-Boundary distance,evolution,security region,transportation network,TransCAD.

Autonomous-synergic Voltage Security Regions in Bulk Power Systems

Determining security/stability boundaries is a common and critical means of preventing cascading failures induced by voltage-related issues,which represents one of the major challenges in bulk power systems.However,traditional approaches suffer from conservative issues and heavy computational burdens.To address these challenges,the concept of an autonomous-synergic voltage security region(AS-VSR)and the corresponding dynamic constraint coefficient pruning(DCCP)computation method,which fully consider the volt/var characteristics of bulk power systems,are proposed in this letter.Both linearized and nonlinearized robust optimization problems are introduced to obtain accurate results.The computational accuracy,time cost,and advantages of autonomous-synergic control are observed in the simulation results.

The Gulf Regional Cooperation after the Cold War

The Gulf cooperation has gained new momentum after the end of the Cold War. However, it also faces various developing difficulties, including the low level of regional institutional cooperation and integration. The regional context of the regional cooperation in the Gulf region is composed by regional security, energy factors and monarchy form of government, in which regional security is the primary motivation which makes it possible for the co-existence in competition of two tendencies in this region: integration and division. The energy element is the most important reason for external powers’ involvement in the region as well as an important part in regional cooperation in the Gulf region. The monarchy is the key point to understand the relationship between the GCC and Iran and the geographical spillover of the GCC. These factors jointly shape the regional cooperation in the Gulf region.

A Comprehensive Security Regime in the Gulf Region: Prospects and Challenges

In international politics,regional initiatives to establish peace and security have been recognised as more appropriate and pragmatic in the present complex interconnected interdependent security scenario.Regional security regimes initiated and promoted both by regional and extra-regional powers for resolving,preventing and managing crises that had grown and nurtured in the regional landscape.Conceptually,comprehensive security regimes,the hybrid of both idealist and realist schools of thought of international relations,are preferably the unique one among all other security regimes.The best example of a comprehensive security regime is the Organisation for Security and Co-operation in Europe.Practically,the dynamic nature of Gulf regional security has become a matter of discourse to ponder upon whether the region is transforming itself on various fronts or whether regional security regimes should be explored to overcome the ongoing multiple security challenges on multidimensional aspects.Scholars have recognised Gulf security as a sub-regional security complex of a larger area which must be dealt with separately.Thus,using this conceptual framework the paper attempts to explore the feasibility of the establishment of a comprehensive security regime in the Gulf Region which can address all three levels of insecurity,regional,state and individual thereby transcend the state-centric approach to security and create security based on multi-sum principles and not on zero-sum calculations.

Distribution management system framework based on security region for future low carbon distribution systems

In this paper,a new Distribution Management System(DMS)framework based on security region is proposed.First,the concept of Distribution System Security Region(DSSR)is introduced.DSSR is capable to describe the N-1 security boundary of the whole distribution network,including the secure output range of DGs.This new theoretic tool provides a chance for the implementation of real-time security analysis and active controls in DMS.Second,this paper proposes and describes five security states for distribution system.Third,an upgraded DMS enhanced with DSSR is proposed,which consists of advanced security functions such as preventive and predictive control of the trajectory of operating points.Finally,a practical case is presented to simulate the proposed DSSR-enhanced DMS,in which both the security region of network and the output range of DGs are calculated.Typical security functions are also demonstrated.In conclusion,the new DMS framework aims to help operate the system closed to its security boundary in order to improve the efficiency significantly within same security standard.This work is beneficial for future low carbon distribution systems with high penetration rate of DGs.

A Data-driven Method for Transient Stability Margin Prediction Based on Security Region

Transient stability assessment(TSA)based on security region is of great significance to the security of power systems.In this paper,we propose a novel methodology for the assessment of online transient stability margin.Combined with a geographic information system(GIS)and transformation rules,the topology information and pre-fault power flow characteristics can be extracted by 2 D computer-vision-based power flow images(CVPFIs).Then,a convolutional neural network(CNN)-based comprehensive network is constructed to map the relationship between the steady-state power flow and the generator stability indices under the anticipated contingency set.The network consists of two components:the classification network classifies the input samples into the credibly stable/unstable and uncertain categories,and the prediction network is utilized to further predict the generator stability indices of the categorized samples,which improves the network ability to distinguish between the samples with similar characteristics.The proposed methodology can be used to quickly and quantitatively evaluate the transient stability margin of a power system,and the simulation results validate the effectiveness of the method.

Total Quadrant Security Region for Active Distribution Network with High Penetration of Distributed Generation

The region-based method has been applied in transmission systems and traditional passive distribution systems without power sources. This paper proposes the model of total quadrant security region(TQSR) for active distribution networks(ADN) with high penetration of distributed generation(DG). Firstly, TQSR is defined as a closed set of all the N-1 secure operation points in the state space of ADN. Then, the TQSR is modeled considering the constraints of state space,normal operation and N-1 security criterion. Then, the characteristics of TQSR are observed and analyzed on the test systems with different DG penetrations. TQSR can be located in any quadrant of the state space. For different DG penetrations,the shape and security features of TQSR are also different. Finally, the region map is discovered, which summarizes the features of different types of distribution networks.

Voltage Security Operation Region Calculation Based on Improved Particle Swarm Optimization and Recursive Least Square Hybrid Algorithm

Large-scale voltage collapse incidences, which result in power outages over large regions and extensive economic losses, are presently common occurrences worldwide. To avoid voltage collapse and operate more safely and reliably, it is necessary to analyze the voltage security operation region(VSOR) of power systems, which has become a topic of increasing interest lately. In this paper, a novel improved particle swarm optimization and recursive least square(IPSO-RLS) hybrid algorithm is proposed to determine the VSOR of a power system. Also, stability analysis on the proposed algorithm is carried out by analyzing the errors and convergence accuracy of the obtained results. Firstly, the voltage stability and VSOR-surface of a power system are analyzed in this paper. Secondly, the two algorithms,namely IPSO and RLS algorithms, are studied individually.Based on this understanding, a novel IPSO-RLS hybrid algorithm is proposed to optimize the active and reactive power,and the voltage allowed to identify the VSOR-surface accurately. Finally, the proposed algorithm is validated by using a simulation case study on three wind farm regions of actual Hami Power Grid of China in DIg SILENT/Power Factory software.The error and accuracy of the obtained simulation results are analyzed and compared with those of the particle swarm optimization(PSO), IPSO and IPSO-RLS hybrid algorithms.

Orbiting Optimization Model for Tracking Voltage Security Region Boundary in Bulk Power Grids

A voltage security region(VSR)is a powerful tool for monitoring the voltage security in bulk power grids with high penetration of renewables.It can prevent cascading failures in wind power integration areas caused by serious over or low voltage problems.The bottlenecks of a VSR for practical applications are computational efficiency and accuracy.To bridge these gaps,a general optimization model for tracking a voltage security region boundary(VSRB)in bulk power grids is developed in this paper in accordance with the topological characteristics of the VSRB.First,the initial VSRB point on the VSRB is examined with the traditional OPF by using the base case parameters as initial values.Then,the rest of the VSRB points on the VSRB are tracked one after another,with the proposed optimization model,by using the parameters of the tracked VSRB point as the initial value to explore its adjacent VSRB point.The proposed approach can significantly improve the computational efficiency of the VSRB tracking over the existing algorithms,and case studies,in the WECC 9-bus and the Polish 2736-bus test systems,demonstrate the high accuracy and efficiency of the proposed approach on exploring the VSRB.

Security Structure Transformation in the Asia-Pacific Region and the ASEAN Role

After the end of the cold war, the Asia-Pacific security structure has experienced great changes, especially on the occasion of the current "power-sharing" and "power-shifting" between China and the United States in the Asia-Pacific region, the Asia-Pacific security structure adjustment is especially significant. On the one hand, the Alliance structure with the United States as the pivot has experienced transformation from a hub-spokes system to a network, has formed the hierarchical layout of new alliance, quasi-alliance and potential alliance, On the other hand, emerging economies represented by China and Russia, while reinforcing the existing coordinate security framework, reshape the Asia-Pacific and even the whole Eurasia geopolitical posture through strategic initiatives such as the Belt and Road Initiative, the Eurasian Economic Union. As the third force in the Asia-Pacific security architecture, the Association of South-East Asian Nations(ASEAN) with the construction of a series of multilateral security mechanisms provides dialogue platform for the two security architectures led by major countries, and has also become one of the feasible paths to realize the future holistic security architecture in the Asia-Pacific region. Meanwhile, the major countries strategic competitions have intensified, which has gradually eroded the ASEAN ‘s cohesion, neutrality and even the central position in a holistic security architecture. The future's reconstruction of the Asia-Pacific security architecture needs to find new strategic consensus and reconfirm the ASEAN central position.